Inkjet printers employ printheads in a wide range of applications to form printed documents and, more recently, have found new uses in various types of manufacturing including additive manufacturing systems that are popularly referred to as “3D printers.” Modern inkjet printheads are complex microfluidic devices that often include hundreds or thousands of inkjets, each of which emits drops of ink at precise times in response to firing electrical signals to form high-quality printed images or manufactured articles.
Many printers employ a multi-pass strategy in which a single printhead or array of printheads move over a printed image multiple times to eject ink drops onto the image during each pass. The printheads or the image receiving member that receives the printed image move laterally between each pass to reposition the inkjets in the printheads between each pass so that a single set of inkjets in each printhead can eject ink drops onto different locations in the printed image during multiple passes. In traditional multi-pass printer processes, each printhead forms a portion of the printed image based on a portion of a larger set of two-dimensional image data during a first pass and another portion of the printed image in subsequent passes using interleaving of the image data. For example, in a simple two-pass configuration a prior-art printer uses column numbers 0, 2, 4, 6, etc. in the image data as input data to control the printheads during a first pass. The printer subsequently shifts the printheads laterally and operates the printheads to form the remainder of the image using column numbers 1, 3, 5, 7, etc. in the image data during the second pass.
While multi-pass printing systems are generally known to the art, some multi-pass printing operations cannot be performed using the simple interleaving process that is described above. More complex multi-pass processes do not merely divide the image data into regularly spaced subsets of columns. These multi-pass processes present challenges to the use of traditional printheads since changing the parameters for printing portions of the image data between passes would require extensive and impractical hardware changes to the structures of the printheads themselves. Consequently, improvements to inkjet printers to enable complex multi-pass printing operations without requiring internal changes to the designs of printheads would be beneficial.